: As a vascular surgeon I treat atherosclerosis of leg arteries, known as peripheral arterial occlusive disease (PAOD). PAOD occurs when arteries to the leg become stenosed or occluded, reducing leg blood flow. Subjects experience calf muscle pain with walking, because although the blood supply is adequate to meet the metabolic demands of resting muscle, it is not adequate to meet the increased demands associated with exercise. Leg bypass surgery (femoro-popliteal bypass) increases leg blood flow, but alone does not improve walking abilities and functional status of elderly PAOD subjects. Effective treatment of PAOD will require identification and therapy for other adverse physiological conditions present in elderly PAOD subjects which contribute to their disability. Older subjects also develop sarcopenia, a condition in which muscle mass and function decline with age. At the University of Texas Medical Branch, Dr. Robert Wolfe, a nationally-known authority on leg muscle physiology, is studying sarcopenia in the elderly. He has developed a three-pool model of leg muscle protein metabolism, using infusion of stable isotopes and gas chromatography-mass spectroscopy methodology. He shown that nutritional supplementation (specifically, amino acids) increases leg muscle protein synthesis, and may therefore offer a method for counteracting the effects of sarcopenia. I was recruited to UTMB in 1999, and have formed a collaboration with Dr. Wolfe. In this study, I am proposing to investigate the relationship between PAOD and leg muscle protein synthesis in elderly subjects with PAOD. It is my hypothesis that reduced leg muscle blood flow associated with PAOD will limit the availability of amino acids to leg muscle, and thus further impair protein synthesis. Femoro-popliteal bypass surgery, by increasing blood flow, should increase delivery of amino acids to muscle and hence ameliorate the effects of sarcopenia. It is my ultimate hope that the combined interventions of bypass surgery and nutritional supplementation with amino acids can be used to improve overall functional status of these elderly Americans.